The present invention refers to a manually operated dispensing device for use with a double cartridge for dispensing two-component chemical systems, the device comprising a double thrust ram comprising a toothing and a drive means jointly acting on the double thrust ram and being actuated by a trigger lever, said drive means having a drive member which comprises a toothing acting on the toothing of the double thrust ram, an arc compensating element being arranged between the drive member and the trigger lever, wherein the drive member is guided in such a manner.
Such a dispensing device is already known from EP-A-0,615,787 to the same Applicant. This device had certain advantages over the prior art known at that time in that it could be manufactured with lower cost parts from plastic materials due to the simultaneous meshing of a plurality of teeth. However, it has now been found that this device is still able to be substantially improved, and that in particular jamming, which is caused in the guide members by having a linear engagement movement, is a problem during the use under high dispensing forces. In addition, high jamming or tilting moments are created in that the driving dog must be guided with respect to the housing by an additional slider whose connecting link is disposed, particularly when the supply cylinders of the cartridges have the same or only slightly different diameters, in a disadvantageous manner below the center line of the reactive force, and that the lateral force impact point of cartridges having different diameters, especially widely different cylinder diameters, is not appropriately located. This results in all cases in a substantial loss of mechanical efficiency.
Another dispensing device has become known from U.S. Pat. No. 5,314,092, wherein the thrust rams acting on supply cylinders having different diameters are not symmetrically disposed but are offset to the side having the higher reactive forces; however, the driving arrangement is totally different from that of the present invention and does not provide a compensating link.